A and not B circuit

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Thread Starter


Joined Jan 17, 2016

This is a little circuit that I want to have on my motorbike.

I have a set of 3 red LED lights and a set of 3 blue LED lights.

A is a switch that turns on and off the blue lights. (Lights)
B is a button which turns on the red lights. (Brakes)

When B (brake) is pressed it should turn off A. I already tested that is A and not B.

My problem is I need to put it on a circuit and I'm not sure how to make a not gate. I read is a PNP, and I cannot use diodes.
I haven't done circuits in 15 years, and I completely forgot everything. I have been wrongly suggested an XOR gate that I have made out of diodes, to realise later that was not what I was looking for. I cannot draw the schematics by myself.

Can someone please help me?


Joined Mar 30, 2015
Welcome to AAC!

You posted in the Homework Help forum. If it's homework, you need to post your work. If it isn't, the Automotive or General forums would be more appropriate.

In any case, a schematic or block diagram would be appreciated.


Joined Mar 31, 2012
You have two functions, one for the blue lights and one for the red lights.

Which function are you saying that AB' is for?

What do your switches do when activated? Do they pull a terminal HI or do they pull it LO?
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